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I purchased a semi-automatic espresso maker that has a perplexing electrical issue.

Discussion in 'Troubleshooting and Repair' started by Doc_Shultz, Jul 24, 2017.

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  1. Doc_Shultz


    Jul 24, 2017
    I purchased a nearly mint condition Gaggia Classic espressio machine last week from a couple that had only used it 4-5 times in the nearly 20 years they have owned it. This unit is 120V 60HZ 1425W, two pronged, and was manufactured in 1998, but the design and components used in the unit have not changed in this time period (wiring has changed as you will see). On the second day of using it, I noticed that I was recieving a mild electronic shock to my forarm when I was steaming milk (felt like I was running my forarm against something sharp), the stainless steel steam wand touching the stainless steel milk carafe, which in turn was in my hand, and my forarm (same arm) was bushing against the stainless steel door on my fridge. I could not find my volt meter to figure out how big of a leak was occuring, but I could find my electric fence tester, which has a small light bulb to check that an electric fence is live. I confirmed it was the espresso machine and not my fridge first, then I opened the top of the espresso machine and checked to see if there was any particular wire, or electronic that might be leaking into the boiler, and in turn, steam wand. Nothing stood out to me, so I checked a Gaggia forum, and found one other person with a unit about the same age as mine, theirs was doing something similar, and they took it to a small appliance electrician that discovered their line and neutral wires were switched from what they should be, they switched them, and they no longer had a current leak.

    This lead me to carefuly look at how my unit was wired, compared to the factory wiring diagram, and I found they have changed their wiring layout compared to how mine is, but there are many similaries. One similarity is that the initial two wires (line and neutral) that lead from the plug socket, go to the same initial locations in the machine, but were switched in my unit. Meaning the neutral wire was going to the on/off switch, and the line wire was going to the thermo cut-off fuse. Using some protective gear, I switched the line and neutral wires at the plug and functioned tested the machine, everything works, and I no longer have a current leak.

    My question is this, why did the machine function normally with reverse current flow? And why did switching the current flow resolve the current leak?

    I have attached the factory wiring diagram(ev00), the wiring diagram of my unit currently after switching the line and neutral wires (1998), and a photo from above the unit to show what I am working with (I accidently cropped out the plug socket attachments, but they are the grey and blue wire at the top of the image next to the black hose).

    *edited for clarity

    Attached Files:

    Last edited: Jul 24, 2017
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    Jan 21, 2010
    You don't have line and negative. You have line and neutral.

    In many countries neutral is earthed, but it is not safe to rely on it.

    Can you plug it in the other way around?
  3. Doc_Shultz


    Jul 24, 2017
    You are correct, line and neutral, and no, I cannot plug it in either way.

    I edited my original post to change negative to neutral.
    Last edited: Jul 24, 2017
  4. Bluejets


    Oct 5, 2014
    Don't play with it, get a qualified electrician to sus it out.
    Should have an earth somewhere unless double insulated.
    Chances are it was imported from some European country without any checks and balances on the safety level of appliances.
    Leakage current is more than likely emanating from the heaters BUT only a qualified electrician will be able to test it for you, verify and advise on course of action.
    While he is there, get some safety switches installed on your switchboard. Just might save your life one day.
  5. Doc_Shultz


    Jul 24, 2017
    They are crafted in Italy. They make a 230v for the European market that has a 3 prong, but the 120v does not. Intrestingly the solenoid valve has a 3rd ground prong with nothing attached to it. As I was saying before, considering that no components have changed in these units, and Gaggia was bought out by Philips in 2015, and they have not changed any components, or added any additional safety components, I am confident that this meets any safety regulations in the US. I appreciate the abundance of caution regarding taking it to an electrition, I will likely take it to one of the electrical engineers that I work with to see what they think, but I was hoping to satisfy my own curiosity before then.
  6. Bluejets


    Oct 5, 2014
    Engineers may not be conversant with supply authority regulations whereas a local electrician will be experienced in dealing with this type of thing on a daily basis.
    Doc_Shultz likes this.
  7. Irv


    Jun 7, 2017
    Did your ground fault interrupter not trip?
    A good rule to follow, especially with anything old, metal, and which involves water, is to always use a GFI.
    Doc_Shultz likes this.
  8. Tha fios agaibh

    Tha fios agaibh

    Aug 11, 2014
    To be legally sold on the market it should have a UL or other Nrtl listing that makes sure it's wired safely. It does sound like it was wired incorrectly. Thankfully, no one was hurt or killed In this case.

    Technically a two wire circuit does not have a neutral but a "grounded" conductor.(Not to be confused with an equipment ground often used on a three prong plug)
    A neutral only carries the unbalanced current back to its source where there are more than one ungrounded (hot) conductors. Therefore it is not a neutral in this case.

    The "gounded" wire should go to the wider prong of a polarized plug (mechanically only plugs in one way) and carry the return current back to source. It should not go to the switch.

    The ungrounded (hot) wire should go to the narrow prong and not have contact with any exposed conductive parts.

    The reason you get a shock is because the hot is exposed on the metal and you become the return path.
    If wired correctly and the hot touches an exposed metal part, the ground is the return path and it will trip the circuit breaker.
  9. Frank223


    Apr 28, 2021
    Sorry, if it's too late and thx to the thread, pals! I bring a Gaggia Babila year ago from Italy also. Same problem. Electrician said that it's impossible to use it here due to local standards and peculiarities in connection. Adapters and switches don't solve it. Lost $1600, what a drama...
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